With continuous growth of an Internet Protocol (IP) service, pressure on an IP backbone network continuously increases. A conventional synchronous digital hierarchy (SDH, Synchronous Digital Hierarchy) network also steadily evolves into an intelligent automatically switched optical network (ASON, Automatically Switched Optical Network).
A key problem for a routing domain to access an optical network is to ensure that a working trail and a protection trail in the optical network do not overlap. At present, access by the routing domain to the optical network is implemented mainly by using an overlay (OVERLAY) model. In the OVERLAY model, layer separation between an optical domain and a routing domain enables separate running of the optical domain and the routing domain; information isolation between the optical domain and the routing domain enables very good access security of the optical domain.
However, because information is completely isolated between the optical domain and the routing domain, when the routing domain accesses the optical domain, for protection of various types of tunnel triggered and established by the routing domain, an effective mechanism is required to ensure that a working trail and a protection trail that are of the tunnels do not cross or overlap in the optical domain. To resolve this problem, in the prior art, information about a trail that is of the working trail and is in each optical domain needs to be saved into a head-end router; in addition, when a protection trail of the working trail is established, a protection trail establishment request sent by the head-end router carries the information about the trail that is of the working trail and is in each optical domain, thereby ensuring that a trail that is of the protection trail and is in each optical domain and that of the working trail and is in each optical domain do not overlap.
However, in such a trail establishing manner, information about a trail that is of a working trail and is in an optical domain needs to be leaked to a routing domain, which can still cause inter-domain leakage of information in the optical domain, thereby reducing access security of the optical domain.